IPM Rotor Core Plate Structure for Secure Magnet Retention
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Solution Overview
Problem
Conventional rotors fail to appropriately hold permanent magnets due to deformation of protrusion portions, leading to reduced holding force and potential magnet damage.
Innovation Solution
A rotor design featuring core plates with first and second deformation permission portions that allow the protrusion portions to deform in opposite directions, ensuring proper magnet retention and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protrusion portion is used to hold the magnet in the magnet insertion hole, then the magnet can be retained in the rotor, but the protrusion portion may be plastically deformed into a bent state during magnet insertion, causing the tip end to be held between the magnet and the magnet insertion hole, which reduces holding force and may damage the magnet
Solution Approach 1:
The rotor is divided into multiple core plates stacked in the thickness direction, with each core plate containing a protrusion portion. This segmentation allows the deformation to be distributed across multiple protrusion portions rather than concentrated in a single protrusion, reducing the risk of tip end deformation being trapped between the magnet and magnet insertion hole.
Solution Approach 2:
The inner surface of the magnet insertion hole is provided with deformation permission portions at specific locations where protrusion portions are present. These deformation permission portions locally increase the compliance of the magnet insertion hole, allowing the protrusion portions to deform elastically in the radial direction without causing plastic deformation or tip end trapping.
2Stability of the object's composition
If the protrusion portion is made rigid to maintain its holding shape, then the holding structure is stable, but it cannot deform to accommodate the magnet insertion process, leading to tip end deformation and reduced holding force
Solution Approach 1:
The deformation permission portions are formed as thin-walled structures on the inner surface of the magnet insertion hole. These thin-walled structures provide flexibility that allows the protrusion portions to deform elastically during magnet insertion while maintaining their overall structural stability and holding capability.
Solution Approach 2:
The deformation permission portions enable the magnet insertion hole to dynamically adapt its shape during the magnet insertion process. The inner surface can elastically deform to accommodate the protrusion portions and then return to its original shape, providing a dynamic response that maintains both structural stability and insertion precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design effectively maintains magnet holding force and prevents damage by allowing controlled deformation of protrusion portions, ensuring stable magnet placement.
Implementation Method 1
a first deformation permission portion which is located in a position in an opposite direction to a protrusion direction of the first protrusion portion with respect to the first protrusion portion when the rotor core is viewed from the axial direction and which permits deformation of the first protrusion portion in the opposite direction
Data Source
AI summary
A rotor includes core plates, a hole, and a magnet in the hole. The core plates include a first core plate and a second core plate frontward of the first core plate. The first core plate includes a first hole, a first protrusion protruding inward of the first hole, and a first portion located in an opposite direction to a protrusion direction of the first protrusion as viewed from the axial direction and permitting deformation of the first protrusion in the opposite direction. The second core plate includes a second hole, and at least one of a recess recessed in the opposite direction and overlapping the first protrusion as viewed in the axial direction, or a second portion located in the opposite direction with respect to the first protrusion as viewed in the axial direction and permitting deformation of an inner surface of the second hole in the opposite direction.